Geant 4 and Microelectronics – Recent Successes, Looming Concerns - PowerPoint Presentation

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Geant4 and Microelectronics – Recent Successes, Looming ConcernsRobert Weller, Robert Reed, Mike King, Marcus Mendenhall, Makoto AsaiSupported in part by the DTRA Basic Research Program 2014 Geant4 Space Users Workshop

Energetic Electron-Induced Single-Event Upsets in SRAMs

Energetic electron

creates e-h pairs

Particle Strikes Sensitive

Node of SRAM

Circuit Transient Response

Results in Error

Single Electron-Induced SEU

Increasing Sensitivity of SRAMs

65 45 32 22 16

Motivation For Electron-Induce SEU

Critical

charge estimates for 22 nm on the order of 0.1

fC

– 0.35

fC

at nominal supply voltage

Devices are becoming increasingly sensitive to lightly ionizing particles

Low-energy Protons

Muons

MRED simulations suggested

electrons can deposit energy in excess of critical charge

estimates

- 2.6

keV or 0.12fC

10

keV

electron

50 nm

Cube

Experimental Method #1 – X-ray Irradiation

28 nm and 45 nm SRAMs

X

-rays used to generate secondary energetic electrons

Dose rate of 100 rad(SiO

2

)/

min

Reduced bias testing

Devices were designed and verified experimentally to be functional at all supply voltages used in this experiment

Incident

X-ray

Energetic Electron

Sensitive

Volume

Upsets in 28 & 45 nm SRAMs

SEU probability

Eliminated TID, photocurrents, and functionality as source of observed errors

No significant parametric degradation; power supply current stable

Experimental Method #2 – Electron Irradiation

Arnold Engineering Development Center

Space Threat Assessment

Testbed

(STAT

)

Electrons

, protons, photons, and others

AEDC

Electron-Induced SEUs

28 nm

SRAMs

100

keV

and 40

keV

electrons

Flux = 2.6 × 10

7

cm

-2

s

-1

Fluence

= 1 × 1010 to 5 × 1010

cm

-

2

Reduced bias testing

Condition

SEU Probability

Standard

Error

0.45 V, 100

keV

1.71E-07

1.19E-08

0.5 V, 100

keV

5.04E-08

7.06E-09

0.45 V, 40

keV

3.13E-07

2.55E-08

Experimental Method #3 – Sr-90 electron sourceThe Use of Strontium-90 Beta Radiotherapy as Adjuvant Treatment for Conjunctival MelanomaCohen VM, Papastefanou

VP, Liu S, Stoker I, Hungerford JL - J Oncol (2013

Potential Space Environments

Solar

activity (solar flares, CMEs, solar wind, photons)

Trapped

particle Environment (Earth, Jupiter, etc..)

Bremsstrahlung

produce by primary environment interactions with S/C

Beta

decay in packaging

Activated

nuclei in S/C

Local delta-rays (generated by heavy-ions)

Shower produced by high-energy (~

TeV

)

ions interacting with S/C

Conclusions

Provided evidence of single electron-induced SEU in 28 nm and 45 nm technologies

Electron-induced SEU primarily a concern for low-power applications, may impact more sensitive current generation ICs at nominal supply

voltage

Modeling

of

electron transport down to very low energies may be an important issue for future technology

Need to identify

critical space radiation environments

Cubesat Program Update

Goal: Provide a low cost on-orbit system to improve our understanding of the impact of space radiation environments on satellite components and systemsOne system delivered for S/C integration One slated for summer 2014 deliveryAnother TBD experiment schedule for early 2016Satellite Program OverviewWarren - Cubesat14

Vanderbilt provides payloadCubeSat partner provides spacecraft busRadFxSat ConceptExample PayloadExample Spacecraft

Warren - Cubesat15

Senior Design Teams2012 teamDesigned an latchup experiment that will be flown on the RadFx-1 2013 teamPreliminary design of an SRAM tester2014 team Evaluated commercial CubeSat S/C for radiation effects

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